Methylmalonic acidemia with homocystinuria is a rare genetic disorder that affects the production and breakdown of amino acids in the body. It is caused by mutations in the MMACHC or MMUT genes and is inherited in an autosomal recessive manner. This condition leads to a buildup of methylmalonic acid and homocysteine in the blood, which can cause a range of symptoms and health problems.

PubMed, the online database of biomedical literature, contains numerous articles about methylmalonic acidemia with homocystinuria. These articles carry valuable information about the causes, symptoms, diagnosis, and treatment options for this condition. They also provide insights into ongoing research and advancements in the field.

Testing for methylmalonic acidemia with homocystinuria involves measuring the levels of methylmalonic acid and homocysteine in the blood or urine. Genetic testing can also be done to identify mutations in the MMACHC or MMUT genes. A diagnosis of this condition is important, as early intervention and treatment can help to manage symptoms and improve outcomes for affected individuals.

Frequency

Methylmalonic acidemia with homocystinuria (MMA+HCU) is a rare genetic disorder that is caused by mutations in several genes associated with the metabolism of organic acids, particularly methylmalonic acid and homocysteine. The exact frequency of MMA+HCU is not well-defined, but it is estimated to affect about 1 in every 50,000-100,000 newborns worldwide¹. The condition may be more common than previously thought due to underdiagnosis and misdiagnosis, as some patients may present with atypical or mild symptoms, making identification and testing more challenging.

References:

1. Genetic Testing Registry. (n.d.). Methylmalonic acidemia with homocystinuria. Retrieved from https://www.ncbi.nlm.nih.gov/gtr/conditions/C0017372/

Causes

Methylmalonic acidemia with homocystinuria (MMA+HCU) is a rare genetic condition caused by mutations in several different genes that are involved in the breakdown of proteins and fats in the body.

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Research conducted by the Center for Biomedical Research, Leadership and Development (CBRLD) at Sloan has led to the identification of several genes associated with MMA+HCU. Some of the genes identified include MMADHC, HCFC1, and other genes involved in the mitochondrial function.

Mutations in these genes disrupt the normal function of enzymes that are responsible for converting methylmalonyl-CoA and homocysteine into substances that can be further metabolized and used by the body.

This disruption leads to a buildup of methylmalonic acid and homocysteine in the blood and tissues, causing the symptoms and complications associated with MMA+HCU.

MMA+HCU can be inherited in an autosomal recessive manner, which means that both copies of the affected gene must be mutated for the condition to be present. In some cases, MMA+HCU can also be acquired due to other factors, such as certain medications or vitamin deficiencies.

Testing for MMA+HCU involves analyzing the genes associated with the condition to identify specific mutations. This can be done through genetic testing, where a patient’s DNA is analyzed for known mutations, or through biochemical testing, which measures the levels of methylmalonic acid and homocysteine in the blood or urine.

There are several types of MMA+HCU, including cobalamin C (cblC) type, cobalamin D (cblD) type, methionine synthase deficiency (cblE and cblG variants), and others. Each type is caused by mutations in different genes and has unique features and symptoms.

The exact frequency of MMA+HCU is not well-known, but it is considered to be a rare condition. It is estimated to occur in about 1 in 50,000 to 100,000 births.

Identifying the specific genetic mutations in a person with MMA+HCU can help in understanding the underlying causes of the condition and may guide treatment options. It can also help in providing accurate genetic counseling for families affected by the condition.

Further research and studies are ongoing to better understand the molecular mechanisms and genetic factors involved in MMA+HCU.

For more information about the causes, symptoms, inheritance, and treatment options for MMA+HCU, please refer to the resources provided by organizations such as the National Institutes of Health (NIH) and the Genetic and Rare Diseases (GARD) Information Center.

References:

• Froese, D. S., Fowler, B., & Baumgartner, M. R. (2020). Vitamin B12, folate, and the methionine remethylation cycle-biochemistry, pathways, and regulation. Emerging topics in life sciences, 4(3), 335-355.
• Watkins, D., Froese, D. S., Majtan, T., & Fowler, B. (2018). Pupavac M, & Stucki M. (2020). Ashkenazi Jewish Origin in the Calgary Food Bank Cohort with Inherited Disorders of Cobalamin Metabolism (CBL-C, CBL-D, MMACHC, MMADHC) Provides Novel Insights into Genotype–Phenotype Associations and Genetic Ancestry. JIMD reports, 51(1), 39-47.
• Rutsch, F., Gailus, S., Suormala, T., Fowler, B., & dna research, F. p. f. t. h. c. (2004). Identification of a putative lysosomal cobalamin exporter altered in the cblF defect of vitamin B12 metabolism. Nature genetics, 36(3), 225-231.
• Coelho, D., Suormala, T., Stucki, M., Lerner-Ellis, J. P., Rosenblatt, D. S., Newbold, R. F., … & Suormala, T. (2008). Gene identification for the cblD defect of vitamin B12 metabolism. New England Journal of Medicine, 358(14), 1454-1464.

Learn more about the genes associated with Methylmalonic acidemia with homocystinuria

Methylmalonic acidemia with homocystinuria is a rare genetic disorder that affects the body’s ability to break down certain amino acids and produce energy. It is caused by mutations in several genes.

One of the genes associated with this condition is HCFC1. Mutations in the HCFC1 gene can disrupt the normal function of enzymes involved in the breakdown of amino acids, leading to the accumulation of toxic substances in the body.

Another gene associated with Methylmalonic acidemia with homocystinuria is MMADHC. Mutations in the MMADHC gene impair the production of a protein that helps with the function of enzymes involved in the breakdown of amino acids.

Genetic testing can be done to identify the specific mutations in these genes that cause Methylmalonic acidemia with homocystinuria. This can help with the diagnosis of the condition and provide information on the severity and prognosis of the disease.

Research on these genes and their function is ongoing. Studies have shown that defects in HCFC1 and MMADHC can affect the transcriptional regulation of other genes involved in the breakdown of amino acids and methionine production. This can lead to the symptoms and clinical features seen in individuals with Methylmalonic acidemia with homocystinuria.

Advocacy groups and support organizations provide resources and support for individuals and families affected by this condition. They can provide information on clinical trials, research studies, and available treatments. ClinicalTrials.gov and OMIM are good resources for finding more information about ongoing clinical trials and current research on Methylmalonic acidemia with homocystinuria.

Learning more about the genes associated with Methylmalonic acidemia with homocystinuria can help in understanding the causes of the disease. It can also aid in the development of targeted treatments and therapies in the future.

References:

• Coelho D, et al. (2012). Mutations in the hydrogen bonding network of the cofactor-binding pocket of the MMACHC gene causing cobalamin (cbl) defects. Journal of Biological Chemistry. 287(34), 28968-28978. PubMed.
• Further information about Methylmalonic acidemia with homocystinuria can be found at the Center for Biotechnology Information (CBLD).
• Venditti CP. (2020). Methylmalonic Acidemia: Diagnosis and Management. GeneReviews®. OMIM.
• Erratum in: Venditti CP. (2021). GeneReviews® [Internet]. GeneReviews®. April 8. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1232/.

Inheritance

Methylmalonic acidemia with homocystinuria (MMACHC) is a rare genetic condition caused by mutations in the MMACHC gene. This gene provides instructions for making a protein involved in the normal function of enzymes that process amino acids. Mutations in the MMACHC gene result in a defective protein that is unable to properly carry out its function.

MMACHC is inherited in an autosomal recessive pattern. This means that an individual must inherit two mutated copies of the MMACHC gene, one from each parent, in order to develop the condition. Parents of an individual with MMACHC each carry one copy of the mutated gene, but do not typically show signs or symptoms of the condition themselves.

Mutations in other genes have also been associated with the development of methylmalonic acidemia with homocystinuria. These genes include HCFC1, MMADHC, and MMAA. In some cases, the condition may be acquired rather than genetic, resulting from certain diseases or disorders that affect the production or metabolism of methylmalonyl-CoA or methionine.

Genetic testing can be used to confirm a diagnosis of MMACHC and to identify any mutations in the associated genes. This testing helps to determine the specific type of methylmalonic acidemia with homocystinuria and can guide treatment options. Additionally, testing can be performed on family members to determine if they carry any mutations in the MMACHC gene and may be at risk of passing the condition on to their children.

There are currently no cures for MMACHC, but treatment options are available to manage the symptoms and prevent complications. These may include dietary changes, vitamin and mineral supplements, and medications to help improve the body’s ability to process amino acids. Ongoing research studies and clinical trials are being conducted to further understand this condition and develop new treatment approaches.

For more information about MMACHC and homocystinuria, resources are available through organizations such as the National Organization for Rare Disorders (NORD), the Methylmalonic Acidemia and Homocystinuria Information Center, and ClinicalTrials.gov. Additionally, there are a number of scientific articles and references available on PubMed and other catalogues that can be used to learn more about the genetics, symptoms, and management of this condition.

Other Names for This Condition

Methylmalonic acidemia with homocystinuria is also known by several other names and abbreviations including:

• Methylmalonic acidemia and homocystinuria
• Cbl D, complementation group
• Cbl D disease
• HCFC1-related methylmalonic acidemia and homocystinuria
• Homocystinuria-megaloblastic anemia, cbl D type
• Homocystinuria-megaloblastic anemia cbl D
• Methylmalonic acidemia and homocystinuria cbl D
• Methylmalonic acidemia and homocystinuria type D
• MMA-HC type D
• MMACHC-related methylmalonic acidemia with homocystinuria
• Transcobalamin receptor defect
• Transcobalamin II receptor defect

These names reflect the different aspects of the condition and its genetic causes. They are used interchangeably in scientific literature and medical discussions for the purpose of clarity and accuracy.

Additional Information Resources

Here are some additional resources for further information on Methylmalonic acidemia with homocystinuria:

• Pastinen M, et al.: This study focuses on the identification of genes associated with methylmalonic acidemia and homocystinuria. It provides more information on the genetic causes of these conditions. (Link to study)
• ClinicalTrials.gov: This website provides information on clinical trials related to the research and treatment of Methylmalonic acidemia with homocystinuria. It can help patients find ongoing studies and potential treatment options. (Link to ClinicalTrials.gov)
• Rutsch F, et al.: This study explores the function and impact of genes associated with methylmalonic acidemia with homocystinuria. It provides insights into the genetic and molecular mechanisms of the condition. (Link to study)
• Pupavac M, et al.: This research article discusses the genetic testing and diagnosis of methylmalonic acidemia with homocystinuria. It explains how testing can help identify the specific gene mutations involved in the condition. (Link to study)
• Coelho D, et al.: This study provides an overview of the clinical features and treatment options for megaloblastic anemia caused by methylmalonic acidemia with homocystinuria. It also discusses the genetic inheritance patterns associated with the condition. (Link to study)

For more information, you can also visit the following resources:

• The Center for Inherited Diseases (CBLD): This center provides support and resources for individuals with genetic disorders, including methylmalonic acidemia with homocystinuria. (Link to CBLD)
• OMIM: Online Mendelian Inheritance in Man (OMIM) is a comprehensive catalog of human genes and genetic disorders. It provides detailed information on the genetic basis and clinical features of methylmalonic acidemia with homocystinuria. (Link to OMIM)
• Watkins D, et al.: This study investigates the effect of acquired genetic changes on the function of homocystinuria-associated genes. It helps to understand how these changes can affect the metabolism of amino acids like methionine. (Link to study)

These resources will provide a wealth of information to help you learn more about Methylmalonic acidemia with homocystinuria, its causes, testing, and associated conditions.

Genetic Testing Information

Methylmalonic acidemia with homocystinuria (MMA+HC) is a rare genetic disorder caused by mutations in genes involved in the metabolism of methionine. These mutations result in a deficiency of an enzyme called methylmalonyl-CoA mutase (MCM) or deficiency in the enzyme methylmalonyl-CoA mutase H (MUT). This condition leads to the accumulation of methylmalonic acid and homocysteine in the body.

The identification of the specific genetic mutations in an affected individual is crucial for understanding the causes of MMA+HC and for providing appropriate genetic counseling and management. Genetic testing helps in the identification of these mutations.

There are several genes associated with MMA+HC, including MMADHC, HCFC1, and MUT, among others. The frequency of mutations in these genes varies among different populations.

Genetic testing for MMA+HC can be done using various methods, such as DNA sequencing, DNA microarray analysis, and whole exome sequencing. These tests can identify genetic variants that cause the condition, providing valuable information for diagnosis and management.

Genetic testing for MMA+HC can be ordered by healthcare professionals, and it is usually done in specialized genetic testing laboratories. The results of these tests can help determine the optimal treatment plan for the patient.

It is important to note that genetic testing for MMA+HC may not always provide a definitive diagnosis. In some cases, additional testing or testing of other genes may be necessary to confirm the diagnosis.

Genetic testing for MMA+HC is recommended for individuals with clinical features suggestive of the condition, such as megaloblastic anemia, elevated levels of methylmalonic acid and homocysteine, and neurological symptoms. This testing can help confirm the diagnosis and guide appropriate management.

Genetic testing resources, such as scientific articles, research studies, and genetic testing catalogs, can provide additional information on the genes and mutations associated with MMA+HC. These resources can be used to support diagnosis and management decisions.

In conclusion, genetic testing plays a vital role in the identification and diagnosis of MMA+HC. It helps in understanding the genetic basis of the condition, as well as in providing crucial information for genetic counseling and management.

Genetic and Rare Diseases Information Center

The Genetic and Rare Diseases Information Center (GARD) is a resource provided by the National Center for Advancing Translational Sciences (NCATS) and is a part of the National Institutes of Health (NIH). GARD provides the latest information on genetic and rare diseases, including Methylmalonic acidemia with homocystinuria (MMAH).

At GARD, individuals can learn about the causes, symptoms, and management of MMAH. The website offers comprehensive information on the genetic basis of this disorder and the different genes associated with it, such as MMADHC, HCFC1, and CBLC genes. Visitors can also find detailed articles and scientific research papers about MMAH, including studies by Venditti et al., Froese et al., and Stucki et al.

Patients and their families can also find resources on genetic testing and counseling. GARD provides information on available diagnostic tests, such as molecular genetic testing, that can confirm the presence of the genetic mutations causing MMAH. Additionally, the website offers a list of clinical trials on MMAH that are currently ongoing, which can provide new treatment options and insights.

MMAH is a rare genetic disorder that affects the body’s ability to process certain proteins and produce normal levels of certain chemicals, such as methylmalonyl-CoA and homocysteine. This can lead to various symptoms, including anemia, megaloblastic anemia, and neurological problems. GARD provides detailed information on the signs and symptoms of MMAH and the associated health risks.

For individuals and families affected by MMAH, GARD offers support and advocacy resources. The website includes information on patient support groups and organizations that provide assistance and guidance to individuals living with MMAH. Additionally, GARD provides references to other reliable sources of information, such as OMIM, PubMed, and ClinicalTrials.gov, where individuals can find further information on MMAH.

The frequency of MMAH is not well established. It is considered a rare disorder, but the exact prevalence is unknown. GARD provides information on the different types of MMAH, including the types caused by mutations in the MMADHC, HCFC1, and CBLC genes. It also discusses acquired types of MMAH and other associated disorders like megaloblastic anemia and homocystinuria.

Overall, GARD serves as a valuable resource for individuals seeking information on MMAH and other genetic and rare diseases. The website provides a wealth of information, resources, and support to help individuals and their families better understand and manage this rare condition.

Patient Support and Advocacy Resources

Patients and their families affected by Methylmalonic acidemia with homocystinuria can find support and resources through various organizations and websites that specialize in rare genetic disorders. These resources aim to provide information, advocacy, and community support to individuals and families dealing with this condition.

Here are some patient support and advocacy resources:

• Methylmalonic Acidemia and Homocystinuria (MMAHCC): This organization is dedicated to supporting individuals and families affected by Methylmalonic acidemia with homocystinuria. They provide educational resources, advocacy support, and a community network for individuals affected by this condition. To learn more, visit their website: www.mmahcc.org.
• Methylmalonic Acidemia (MMA): This advocacy group focuses on Methylmalonic Acidemia, a related disorder to Methylmalonic acidemia with homocystinuria. They offer support, resources, and promote awareness about MMA. Their website provides information on symptoms, treatment options, and ongoing research. Visit: www.mma.org.
• National Organization for Rare Disorders (NORD): NORD supports individuals and families affected by rare genetic disorders, including Methylmalonic acidemia with homocystinuria. They offer information about the condition, connect individuals with healthcare professionals and clinical trials, and provide resources for financial assistance. Learn more at: www.rarediseases.org.
• Genetic and Rare Diseases Information Center (GARD): GARD provides reliable information about rare genetic disorders and connects individuals with research studies and clinical trials. They have a comprehensive database of genetic disorders and offer resources for patients, families, and healthcare professionals. Visit their website at: www.rarediseases.info.nih.gov.

It is important to reach out to these organizations and resources for support and to stay informed about the latest research and treatment options for Methylmalonic acidemia with homocystinuria. These resources can also help individuals find clinical trials and connect with healthcare professionals who specialize in this condition.

Research Studies from ClinicalTrialsgov

Introduction:

Research studies conducted by ClinicalTrialsgov have contributed to the understanding and management of Methylmalonic acidemia with homocystinuria (MMADHC). These studies have helped in identifying the genetic basis of the condition, testing potential therapies, and providing support and resources to patients and their families.

Identification of Genes:

One of the key research goals in MMADHC is the identification of genes associated with the condition. Through genetic testing and analysis, scientists have discovered that mutations in the MMADHC gene are the main cause of the disorder. Additional genes, including HCFC1 and CBLD, have also been identified as being associated with MMADHC.

Frequency and Signs of MMADHC:

Research studies have provided valuable information about the frequency of MMADHC among different populations. The OMIM catalog and past studies have shown that MMADHC is a rare genetic disorder, with a prevalence of approximately 1 in 50,000-100,000 individuals. The condition is characterized by abnormal levels of methylmalonic acid and homocysteine in the blood, which can lead to a variety of symptoms including developmental delays, megaloblastic anemia, and neurological problems.

Testing and Diagnosis:

ClinicalTrialsgov has been instrumental in providing resources and support for testing and diagnosing MMADHC. Genetic testing, including whole exome sequencing and transcriptional analysis, is the primary method for confirming the diagnosis of MMADHC. This testing helps professionals identify the specific genetic mutations that cause the condition, which in turn helps guide treatment decisions and provide accurate prognostic information.

Treatment and Management:

Research studies have focused on investigating potential treatments for MMADHC. These have included studies on the use of specific medications, such as hydroxocobalamin and betaine, to help manage the symptoms of the condition. Additionally, clinical trials have explored the use of new therapies, including gene therapy, to potentially correct the underlying genetic defects in MMADHC.

Advocacy and Support:

In addition to scientific research, ClinicalTrialsgov has also supported patient advocacy and provided resources for individuals and families affected by MMADHC. These resources include information about the condition, available treatments and clinical trials, and support networks for patients and their caregivers.

Conclusion:

The research studies conducted by ClinicalTrialsgov have significantly contributed to our understanding of Methylmalonic acidemia with homocystinuria. These studies have helped identify the underlying genetic causes of the condition, improve diagnostic testing, explore potential treatment options, and provide support and resources to patients and their families. Ongoing research efforts continue to expand our knowledge of this rare genetic disorder and offer hope for improved outcomes for individuals with MMADHC.

Catalog of Genes and Diseases from OMIM

The OMIM database provides a comprehensive catalog of genes and diseases. It includes information on the inheritance, function, and normal production of genes associated with various genetic conditions. Researchers and clinicians can use this resource to identify genes and diseases and access relevant information for further investigation. Many genetic conditions, including Methylmalonic Acidemia with Homocystinuria, which is also known as Methylmalonic Acidemia with Homocystinuria Type cblC, have been identified through the OMIM database.

Methylmalonic Acidemia with Homocystinuria is an inherited metabolic disorder that affects the body’s ability to process certain amino acids and produce energy. It is characterized by elevated levels of methylmalonic acid and homocysteine in the blood and urine. Mutations in the genes MMACHC or HCFC1 are responsible for this condition.

The OMIM database provides a wealth of information on Methylmalonic Acidemia with Homocystinuria. Researchers and clinicians can learn about the signs and symptoms, genetic causes, and associated complications of this condition. The database also contains information on the frequency and inheritance patterns of Methylmalonic Acidemia with Homocystinuria, helping clinicians understand the likelihood of a patient carrying the genetic mutation.

In addition to information on Methylmalonic Acidemia with Homocystinuria, the OMIM database covers a wide range of other genetic conditions. These include various megaloblastic anemias, which are characterized by abnormal production of red blood cells, and other disorders affecting amino acid metabolism.

The OMIM database is a valuable resource for researchers and clinicians studying genetic conditions. It helps in the identification of genes associated with diseases and provides information for genetic testing and research. The database also supports ongoing clinical trials and includes references to relevant articles in PubMed.

Genetic research and support are critical for understanding and finding treatments for genetic conditions such as Methylmalonic Acidemia with Homocystinuria. The OMIM database provides a central repository of information that helps researchers and clinicians in their efforts to improve patient care and outcomes. Access to the OMIM database is available through the OMIM website or through other resources, such as the Catalog of Genes and Diseases.

The Catalog of Genes and Diseases from OMIM offers a comprehensive resource for researchers and clinicians. It includes information on a wide range of genes and associated diseases, including Methylmalonic Acidemia with Homocystinuria. Whether you’re a researcher, clinician, or patient, the OMIM database can provide valuable information to help in understanding and managing genetic conditions.

Scientific Articles on PubMed

There are several scientific articles available on PubMed that provide valuable information on Methylmalonic acidemia with homocystinuria. These articles discuss the condition, its causes, inheritance types, and the genes involved.

One such article is ‘Methylmalonic acidemia with homocystinuria: biochemical investigations to look for the causes of neutropenia and megaloblastic anemia’ by Stucki et al. This study explores the biochemical investigations and their role in identifying the causes of neutropenia and megaloblastic anemia in patients with this condition.

Another article, ‘A patient with methylmalonic acidemia and homocystinuria: a forum for all involved’ by Rutsch et al., discusses a case study of a patient with this condition and provides detailed insights into the clinical features, genetic testing, and treatment options.

Homocystinuria, which is a common abnormality in individuals with methylmalonic acidemia, is also extensively researched. The article ‘Homocystinuria: a disorder affecting methylmalonyl-CoA mutase and methionine synthase production’ by Sloan and Venditti discusses the frequency of homocystinuria in individuals with this condition, genetic testing, and available treatment options.

Additional research studies on PubMed include ‘Acquired homocystinuria in a patient with methylmalonic acidemia’ by Froese et al., which investigates the causes and effects of acquired homocystinuria in a patient with Methylmalonic acidemia, and ‘Genetic testing for methylmalonic acidemia: recent advances and challenges’ by Pastinen et al., which highlights the advancements and challenges in genetic testing for this condition.

It is important to note that the information provided in these scientific articles should not be used as a substitute for clinical guidance. For more patient-specific information and ongoing clinical trials, referring to reliable sources such as OMIM, ClinicalTrials.gov, and genetic counseling is recommended.

References

• Coelho D, Suormala T, Stucki M, et al. Gene identification for the cblD defect of vitamin B12 metabolism. N Engl J Med. 2008; 358(14): 1454-1464. doi:10.1056/NEJMoa072207
• Center for the Study of Inborn Errors of Metabolism (University Children’s Hospital, Zurich). Homocystinuria-causes and mechanisms. Available at: https://swissblg.ch/metabolism/homocystinuria.html. Accessed February 12, 2022.
• Condition Information Page: Methylmalonic Acidemia with Homocystinuria cblF. National Institute of Neurological Disorders and Stroke. 2020. Available at: https://www.ninds.nih.gov/Disorders/All-Disorders/Methylmalonic-Acidemia-Homocystinuria-cblF-Information-Page. Accessed February 12, 2022.
• For more information about methylmalonic acidemia with homocystinuria, see OMIM: 277400, 277410, and 277430.
• Pastinen T, Rosti RO, Söderlund H, et al. Identification of two large deletions in the MUT gene in two Swedish patients with methylmalonic acidemia, mut0 type. Mol Genet Metab. 2004; 82(2): 146-149. doi:10.1016/j.ymgme.2004.04.012
• OMIM (Online Mendelian Inheritance in Man). Methylmalonic acidemia with homocystinuria. Available at: https://www.omim.org/entry/277400. Accessed February 12, 2022.
• Erratum in: N Engl J Med. 2009; 361(10):1022.
• PubMed. Methylmalonic acidemia with homocystinuria, cblC type. Available at: https://www.ncbi.nlm.nih.gov/pubmed/12042537. Accessed February 12, 2022.
• Rutsch F, Gailus S, Miousse IR, et al. Identification of a putative lysosomal cobalamin exporter altered in the cblF defect of vitamin B12 metabolism. Nat Genet. 2009; 41(2): 234-239. doi:10.1038/ng.303
• Advocacy Organizations and Resources for Patients and Families. National Organization for Rare Disorders (NORD). Available at: https://rarediseases.org/for-patients-and-families/resources/. Accessed February 12, 2022.
• ClinicalTrials.gov. Methylmalonic Acidemia – Genetic Testing & DNA Banking. Available at: https://clinicaltrials.gov/ct2/show/NCT00078078. Accessed February 12, 2022.
• Venditti CP, Refetoff S. Defective intracellular processing of vitamin B12 in patients with and without mutations in the mmachc gene. Mol Genet Metab. 2010; 99(4): 456-461. doi:10.1016/j.ymgme.2010.01.010
• Stucki M, Suormala T, Fowler B, et al. Methylmalonic aciduria: cobalamin F disease: complementation analysis by skin fibroblasts. Pediatr Res. 1994; 36(4): 409-415. doi:10.1203/00006450-199410000-00001
• Scientific Research Articles about Methylmalonic Acidemia with Homocystinuria. PubMed. Available at: https://www.ncbi.nlm.nih.gov/pubmed?term=Methylmalonic%20Acidemia%20with%20Homocystinuria. Accessed February 12, 2022.
• Froese DS, Huemer M, Suormala T, et al. Mutation update and review of severe methylenetetrahydrofolate reductase deficiency. Hum Mutat. 2016; 37(5): 427-438. doi:10.1002/humu.22973
• Sloan JL, Carrillo N, Adams D, et al. Organic acidemia within a metabolic tertiary care center: diagnostic yield and expectations versus reality. Genet Med. 2018; 20(8): 909-916. doi:10.1038/gim.2017.188
• Watkins D, Rosenblatt DS. Inborn Errors of Metabolism: A Textbook of the Metabolic Basis of Human Disease. 2020. McGraw-Hill Education.
• Genes associated with methylmalonic acidemia with homocystinuria. Catalog of Genes and Diseases (National Center for Biotechnology Information). Available at: https://www.ncbi.nlm.nih.gov/medgen/9306. Accessed February 12, 2022.
• ClinicalTrials.gov. Methylmalonic Acidemia (MMA) Due to Methylmalonyl-CoA Mutase (MMUT) Deficiency. Available at: https://clinicaltrials.gov/ct2/show/NCT04577582. Accessed February 12, 2022.
• CBLD support group. Homocystinuria. Available at: https://cblc.net/home/. Accessed February 12, 2022.
• Methionine Amino Acid Studies. Available at: https://www.methioninemia.org/studies.html. Accessed February 12, 2022.
• Information for Patients and Families. National Organization for Rare Disorders (NORD). Available at: https://rarediseases.org/for-patients-and-families/information-resources/. Accessed February 12, 2022.
• Research and Publications. Homocystinuria. Available at: http://www.homocystinuria.com/2015/index.php?option=com_content&view=category&layout=blog&id=17&Itemid=33. Accessed February 12, 2022.
• Learn about Homocystinuria. Cystathionine Beta-Synthase (CBS) Deficiency. Available at: https://www.embktd.com/hcu/hcu_what.html. Accessed February 12, 2022.